National Geographic : 1976 Oct
UR CONTINENT takes you back 4.6 billion years... backward toward cataclysmic beginnings... deep, deep into the time when earth was born. Learn of the ancient rift that tore our land from the supercontinent called Pangaea. Discover how our mountains and hills, beaches and swamps, forests and grasslands were formed... how nature's forces still shape the restless crust on which we live. Follow the grand procession of life from Plants microscopic organisms to primitive sea lilies, without corals, fishes, amphibians, and the includir incredible dinosaurs that live on reigned supreme for a heirs of hundred million years. In Our Continent you visit swamps where predatory dragonflies with 28-inch wingspreads flew over great green plants that turned to coal. You trek with primitive man across the Bering land bridge to behold a continent already blessed with a bewildering diversity of birds, mammals, and flowers. Then you explore the lay of the land from the glacier-gouged Canadian Shield to the Diplod remote Mexican highlands, from the Ice Age record land ar moraine that is Cape Cod across the prairies lived and mountains and deserts to the Pacific, feet. It where earthquakes leave fresh scars to prove swamp; that the continent is still moving, still Wyomi unfinished. (For further details and Table of Colora Contents, see page 574.) 150 mi 572 Trace the shaping of North America itness the nergence life existed for eons flowers, and many, ig ferns and mosses, today. Ferns are ancient water plants. ocus holds the as the longest limal that ever almost 90 roamed s in Utah, ng, and do almost llion years ago. Volcanoes hint the awesome pow at work in our he hearted planet-forc push continents aroun build mountains, change ocear Compare our globe to a soft-boilec egg: shell-like crust, thick middle lai representing the white, a fiery, part] liquid core equivalent to the yolk.